DFA III is a functional oligosaccharide with an effect on promoting the absorption of minerals primarily including calcium, a diuretic effect, and an effect of ameliorating constipation DFA III is a cyclic disaccharide (di-D-fructofuranose-2′,1:2,3′-dianhydride), where the reducing end of each of two fructose molecules is bonded to a hydroxyl group at a position other than the reducing end of the other fructose molecule. DFA III is highly soluble in water at a solubility of 90 to 95% of the water solubility of sucrose, while the sweetness level is about 52% of that of sucrose. Additionally, DFA III is a substance highly resistant against heat and acids.
As one process for producing DFA III, a process for producing DFA III has been proposed, comprising interacting a bacterium of the species Arthrobacter ureafaciens or an enzyme generated by the species with inulin and/or an inulin-containing plant extract to prepare a solution containing DFA III, passing the solution containing DFA III through a column packed with active charcoal to allow DFA III to be adsorbed on the active charcoal, subsequently eluting the column with ethanol to recover a fraction at a high DFA III content and evaporating and drying the fraction (see for example Patent Reference 1).
Another process for producing DFA III has also been proposed, comprising passing inulin and/or an inulin-containing plant extract through a column packed with inulin fructotransferase immobilized on an immobilizing material, to generate a DFA II-containing solution, and subjecting the DFA III-containing solution to a purification step for example with an ion exchange resin or active charcoal to generate a DFA III-containing syrup or an evaporated and dried product (see for example Patent Reference 21.
Furthermore, it is also described that the reaction of inulin with inulase II allows for the industrial production of DFA III at a high purity (see for example Patent Reference 3).
However, absolutely not any of these references tells about the yield of crystallized DFA III. Not any report has been issued about an efficient industrial production of the crystals of DFA III. Therefore, such production has been totally unknown.
Patent Reference 1
JP-B-56-26400
Patent Reference 2
JP-A-1-285195
Patent Reference 3
JP-A-11-43438